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Friday, November 8, 2013

Engineering Milestone: World’s Tallest Building

In the following articles, we will tackle about
different engineering achievement, from world’s tallest building, longest
bridge, biggest building, and the likes. This post is the first of the series,
so let’s start.

The Council on Tall Buildings and Urban
Habitat, an organization that certifies buildings as the "World’s
Tallest", recognizes a building only if at least fifty percent of its
height is made up of floor plates containing habitable floor area. Structures
that do not meet this criterion, such as the CN Tower, are defined as
"towers".

Since 2010, the structure that holds the “World’s Tallest Building” title is the Burj Khalifa (“Khafa Tower”, Burj Dubai) located in Dubai, UAE. It measures 829.8 meters (2, 722 ft). The construction of the building began on September 21, 2004, its exterior was completed October 1, 2009 and its official inauguration and opening was on January 4, 2010.

The
tower was designed by Skidmore, Owings and Merrill, who also designed the Willis Tower (formerly the
Sears Tower) in Chicago and the new One World Trade Center in
New York City. The Burj Khalifa uses the bundled tube design, invented
by Fazlur Rahman Khan. Proportionally, the design uses half the amount of
steel used in the construction of the Empire State Building thanks to the
tubular system. Its design is reminiscent of Frank Lloyd Wright's
vision for The Illinois, a mile high skyscraper designed for Chicago.
According to Marshall Strabala, an SOM architect who worked on the building's
design team, Burj Khalifa was designed based on the 73 floor Tower Palace
Three, an all-residential building in Seoul. In its early planning, Burj
Khalifa was intended to be entirely residential.

Subsequent to the original design by Skidmore,
Owings and Merrill, Emaar Properties chose Hyder Consulting to be the
supervising engineer with NORR Group Consultants International Limited chosen
to supervise the architecture of the project. Hyder was selected for its
expertise in structural and MEP (mechanical, electrical and plumbing)
engineering. Hyder Consulting's role was to supervise construction,
certify SOM's design, and be the engineer and architect of record to the UAE
authorities. NORR's role was the supervision of all architectural
components including on site supervision during construction and design of a
6-storey addition to the Office Annex Building for architectural documentation.
NORR was also responsible for the architectural integration drawings for the
Armani Hotel included in the Tower. Emaar Properties also engaged GHD,[47] an
international multidisciplinary consulting firm, to act as an independent
verification and testing authority for concrete and steelwork.

The design of Burj Khalifa is derived from
patterning systems embodied in Islamic architecture. According to the
structural engineer, Bill Baker of SOM, the building's design incorporates
cultural and historical elements particular to the region such as the spiral
minaret. The spiral minaret spirals and grows slender as it rises. The
Y-shaped plan is ideal for residential and hotel usage, with the wings allowing
maximum outward views and inward natural light. As the tower rises from
the flat desert base, there are 27 setbacks in a spiralling pattern,
decreasing the cross section of the tower as it reaches toward the sky and
creating convenient outdoor terraces. At the top, the central core emerges and
is sculpted to form a finishing spire. At its tallest point, the tower sways a
total of 1.5 m (4.9 ft).

To support the unprecedented height of the
building, the engineers developed a new structural system called the buttressed
core, which consists of a hexagonal core reinforced by three buttresses that
form the ‘Y' shape. This structural system enables the building to support
itself laterally and keeps it from twisting.

The spire of Burj Khalifa is composed of more than
4,000 tonnes (4,400 short tons; 3,900 long tons) of structural steel. The
central pinnacle pipe weighing 350 tonnes (390 short tons; 340 long
tons) was constructed from inside the building and jacked to its full height of
over 200 m (660 ft) using a strand jack system. The spire
also houses communications equipment.

In 2009, architects announced that more than 1,000
pieces of art would adorn the interiors of Burj Khalifa, while the residential
lobby of Burj Khalifa would display the work of Jaume Plensa, featuring
196 bronze and brass alloy cymbals representing the 196
countries of the world. It was planned that the visitors in this lobby
would be able to hear a distinct timbre as the cymbals, plated with 18-carat
gold, are struck by dripping water, intended to mimic the sound of water
falling on leaves.

The exterior cladding of Burj Khalifa consists of
142,000 m2 (1,528,000 sq ft) of reflective glazing,
and aluminium and textured stainless steel spandrel panels with
vertical tubular fins. The cladding system is designed to withstand Dubai's
extreme summer temperatures. Additionally, the exterior temperature at the top
of the building is thought to be 6 °C (11 °F) cooler than at its base. Over
26,000 glass panels were used in the exterior cladding of Burj Khalifa. Over
300 cladding specialists from China were brought in for the cladding work on
the tower.

A 304-room Armani Hotel, the first of four by Armani,
occupies 15 of the lower 39 floors. The hotel was supposed to open on 18
March 2010,but after several delays, it finally opened to the
public on 27 April 2010. The corporate suites and offices were also
supposed to open from March onwards, yet the hotel and observation deck remained
the only parts of the building which were open in April 2010.

The sky lobbies on the 43rd and 76th
floors house swimming pools. Floors through to 108 have 900 private
residential apartments (which, according to the developer, sold out
within eight hours of being on the market). An outdoor zero-entry swimming
pool is located on the 76th floor of the tower. Corporate offices and
suites fill most of the remaining floors, except for a 122nd, 123rd and 124th
floor where the At.mosphere restaurant, sky lobby and an
indoor and outdoor observation deck is located respectively. In January 2010,
it was planned that Burj Khalifa would receive its first residents from
February 2010.

Burj Khalifa can accommodate up to 35,000 people at
any one time. A total of 57 elevators and 8 escalators are installed. The
elevators have a capacity of 12 to 14 people per cabin, the fastest rising and
descending at up to 10 m/s (33 ft/s) for double-deck elevators. However,
the world's fastest single-deck elevator still belongs to Taipei 101 at
16.83 m/s (55.2 ft/s). Engineers had considered installing the
world's first triple-deck elevators, but the final design calls for double-deck
elevators.The double-deck elevators are equipped with entertainment
features such as LCD displays to serve visitors during their travel to the
observation deck. The building has 2,909 stairs from the ground floor to
the 160th floor.

The graphic design identity work for Burj Khalifa
is the responsibility of Brash Brands, who are based in Dubai. Design of
the global launch events, communications, and visitors centers for Burj
Khalifa have also been created by Brash Brands as well as the
roadshow exhibition for the Armani Residences, which are part of the
Armani Hotel within Burj Khalifa, which toured Milan, London, Jeddah, Moscow
and Delhi.

The design is an abstraction of the
Hymenocallis, a flower that has long petals that extend from its center. The
flower is found in tropical and subtropical spots around the world, and its
name means “beautiful membrane” in Greek.

The Burj Khalifa is roughly three times the height
of the Eiffel Tower, 15 times the highest point at Niagara Falls and almost
twice as tall as the Empire State Building.

The actual construction of the
building was done by a South Korean company, Samsung Engineering and
Construction. It took more than 110,000 tons of concrete, 55,000 tons of steel
rebar, and 22 million man-hours to complete the Burj Khalifa.

There was so much rebar used to construct this
building—31,400 metric tons, in fact—that if it were all laid end to end it
would cover more than a quarter of the way around the world.

The building’s exterior is made up of 26,000 individually
cut glass panels. More than 300 cladding experts from China collaborated on the
Burj Khalifa’s cladding system, which was designed specially to withstand the
heat of a Dubai summer.

How do you keep the world’s tallest
building—covered in 24,000 reflective windows—clean? For the Burj Khalifa,
36 cleaners board 12 13-ton machines that move along tracks attached to the
outside of the building, at heights of 20,000 feet. There actually was a competition
for the cleaning gig, and Australian company Cox Gomyl won.

It comes as no surprise that the world’s tallest
building consumes a whole lot of resources. The Burj Khalifa is supplied
with an average of 250,000 gallons of water every day, and can reach an electrical
demand equal to that of 360,000 100-watt bulbs burning at once.

The Burj Khalifa’s designers anticipated the
difficulty of running down 120 flights of stairs in an emergency, so they
developed the first-ever elevator system for a mega–high rise that can
carry out controlled evacuations for some fire or security issues.